Vulcanizable rubber compositions have been manufactured for many years wherein a polymer, that is vulcanizable rubber, is included along with suitable rubber additives, for example, a tackifier, a vulcanizing agent, like sulfur, and various fillers. As is known, this so-called compound, or vulcanizable rubber composition or green rubber, is then subjected, in a mold, to heat and pressure to effect curing and formation of the final product, such as, for example, tires.
In order to form high quality products, it is necessary to use tackifiers in the vulcanizable rubber composition. These tackifiers promote the adherence of different pieces of the green or uncured rubber compound together and thereby allow convenient and precision build-up of plural pieces of rubber. The tackifiers used in the past are generally rather sophisticated organic chemicals and oftentimes are quite expensive. Frequently, in order to obtain the needed degree of tack, these tackifiers are used in substantial amounts, even to the point where they detrimentally impact on the ultimate properties of the vulcanized rubber composition.
Thus, it will be seen that there is a need in the art for providing tackifiers for vulcanizable rubber compound compositions wherein the tackifiers have improved tack per unit of weight and also are inexpensive and minimize undesirable side-effects.